Feb. 1907.] 97 Timbers. 



when alkaline washes are used ; but it requires more energetic boiling ; the pro- 

 portion of alkali is doubled, and the boiling done at a pressure of 165 lbs. A little 

 chlorine is also required for the bleaching. In this country common " news" requires 

 to have about 20% of sulphite to hold it together on a fast-running machine. In 

 America it can be produced with 100% mechanical, the reason being that mechanical 

 coming direct from the gardens has greater felting powers than if converted into 

 pulp and shiped to this country. This point is a matter of considerable economical 

 importance, and probably accounts for the difference got with fast-running machine 

 between England and the United States of America. 



I have explained that mechanical or ground wood pulp can only be used alone 

 for inferior grades of paper, and must be used direct from the grinders on to the 

 paper machines. A combination of about 70-80% of mechanical wood pulp fibre, and 

 20-30% of chemical produce the " news " on which our daily newspapers are printed. 

 The manufacture of wood pulp is undoubtedly a most interesting study which has 

 closely occupied the minds of eminent scientists and experts for years, and new facts 

 are being brought to light. Indeed, wood pulp as a field of research, seems inex- 

 haustible. Quite recently 1 visited the important paper and pulp mills of the Munksjo 

 Company at Jonkoping, in Sweden, where the manufacture of what is termed 

 " Kraft " paper was discovered, tradition says by accident, although Mr. Hagborg 

 says that the method was arrived at after long and careful experimen t. Wood pulp 

 is used solely in the production of many thousands of tons of boards, which are used 

 by book binders, paper box makers, and others. I might mention that in the various 

 pulp-producing countries many millions of pounds sterling are invested in the pro- 

 duction of pulp. A large proportion of this is British capital. Reverting to the 

 question of 



GROUND WOOD, 



or, as it is generally known in this country, mechanical, it may be said that the 

 method of "logging and of conveying the cut timber from the place where it falls into 

 the mill, is governed largely by local conditions which I shall deal with subse- 

 quently. But when once the wood is at the mill, the method of transforming it into 

 mechanical wood pulp is today a simple one. The blocks of wood are put into a 

 barking machine, a common form of which is provided with three knives upon a 

 rapidly revoling drum. The blocks of wood aie brought in contact with these knives 

 and it is essential that the bark is thoroughly cleared away, otherwise the pulp will 

 show dark spots. Knotty wood is also objectionable, and as far as practicable, knots 

 have to be removed, and in many mills this is achieved by means of a revolving auger 

 or a spoon-shaped auger. The wood is cut into blocks by circular saws, and it should 

 be finally split in order that the inside of the wood may be examined, as it is unde- 

 sirable that any decayed timber shall be made use of. Only sound wood should 

 properly be used, as the effect of rotten wood is sure to be detrimental to the pulp. 

 The actual grinding of the wood is simple. Every kind of machine for grinding 

 consists of a grind stone (of sand stone), which runs at a very rapid rate, and against 

 the surface of which the wood is pressed, the latter being kept constantly wet by a 

 copious water supply. The wood is fed into what are termed pockets, and placed so 

 that its vascular bundles lie parallel to the surface of the grindstone. The latter, in 

 revolving, tears from the wood individual vascular bundles, and occasionally large 

 splinters. The mass is carried by the water into a vat, in which the revolving stone 

 is placed, and from there to the sorting contrivances, by which various sized parti 

 cles of wood are separated from each other. In some modern grinders, the stone is 

 fixed to a vertical shaft, but most authorities consider a horizontal position prefer- 

 able. If time permitted, I would like to have described in detail the various types of 

 machine in use in various countries, of which the principal ones are : Volter's, 

 Qser's, Toith's, Freitag*s, Abadie's and others. In this connection it is highly essential 



